1. Field of the Invention
The invention relates to a flexible pipeline for transporting a pressurized flowable medium, which consists of two pipes of metal which are corrugated. transversely of their longitudinal direction, an inner pipe and an outer pipe which are arranged with the inclusion of an annular gap concentrically relative to each other, and in which a vacuum insulation is mounted in the annular gap between the two pipes (EP 2 253 878 B1).
2. Description of the Related Art
Such a pipeline is required, for example, for supplying superconductive magnetic systems or cryo pumps with a cooling medium. The pipeline is supposed to be flexible and should also have a rather long length. For bridging the length, the cooling medium must be transported with an increased pressure in the inner pipe. This is also true for other media, such as water. The increased pressure of the respective medium, for example starting at 25 bar, can easily lead to a plastic deformation of the inner pipe and consequently, may to some extent, lead to a deflection of the same from its central position. The efficacy of the vacuum insulation is permanently reduced by such a plastic deformation.
U.S. Pat. No. 6,607,010 B1 describes a vacuum tight annularly corrugated pipe of synthetic material or metal which, for its stabilization, is lined with a nonwoven fabric which is at both ends thereof attached to the pipe. For protecting the pipe and for its use as a pressurized pipe, it also possible to arrange, on the outside around the pipe, a nonwoven fabric which extends over the entire length of the pipe. This nonwoven fabric is also attached at both ends of the pipe to the same.
The pipeline serving for transporting a deep frozen medium according to the above mentioned EP 2 253 878 B1 does not have the above described deficiency. Over the inner pipe of this known pipeline is arranged a second pipe system which consists of an inner metal pipe, which is corrugated transversely of its longitudinal direction, and an outer metal pipe arranged at a distance and coaxially with the same which is also corrugated transversely of its longitudinal direction. The vacuum insulation and the outer pipe of the pipeline are located above the outer pipe of the second pipe system. The inner pipe of the second pipe system is arranged spatially tight at the inner pipe of the pipeline, and holds the same with the intermediate arrangement of a spacer member of insulating material immovably in its relative position. This known pipeline has been found useful in practice. However, it is of complicated construction.